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稜 skin turtle Division (Dermochelyidae) and the turtle Division (Cheloniidae) of the sea-dweller turtle.Adapt to the aquatic life, limb into fin-shaped, conducive to swim.Generally only during the breeding season out of water coming ashore.Female turtle eggs will be digging holes at the beach.稜 skin turtle (Dermochelyscoriacea) was extant turtle species of approximately 2.1 meters (7 ft), weighing about 540 kilograms (1, 200 pounds).End of the two former fin is approximately 2.7 between span meters.The most broadly long up to 3 meters, weighing about 900 kg.Composed by strut carapace, slightly overburden to sepia or black leather quality skin.Back 7 obvious longitudinal 稜, there are 5 of the abdomen.On the world's oceans, longer than swimming, and omnivorous.
稜 Dermochelys coriacea turtles (skin)
Sea turtles are turtles turtle species.Presence in Atlantic, Pacific and Indian oceans.Made in China, belonging to the Japan Sea turtles from Shandong, South to have distribution Beibu Gulf offshore.Up to the life of 1 m, maximum size of around 150-year-old ... with a pair of overhead his forehead squamous cell.Forelimb propeller, extremities as taking longer than the hind limbs, medial, toe has got a claw.Head, neck and limbs could shrink into KAB.Feed mainly on seaweed.Living in the Atlantic, Pacific and Indian Ocean, to land their eggs, hatchling.Meat edible fats can refinery.As a national class two animal protection.
Turtle maxillary-mandibular flat out, slightly curved to the bait, JAWS rim jagged notched.On the forehead and squamous cell 1.Heart-shaped carapace assumes.Arrange Scutum inlay.Vertebral shield 5 slices; rib guilders per side 4 tablets; 11 per side margin shield.The paddle-shaped extremities.Forelimb longer than the hind legs, claws medial with 1.Male tail is long, one half of $ body length.Forelimb claws large, curved hook.Carapace olive or brown-coloured stripes, clutter-taking; abdominal KAB yellow.Living in the upper sublittoral.To fish, cephalopod animals, crustacea and algae, etc.The annual 4 to 10 months for the breeding season, often in the vicinity of the mating surface of the reef, 3 ~ 4 hours.Female at night to get to shore on the beach, forelimb to dig a deep and body high considerable Tai Hang, pits, and then to hind alternating to dig a diameter 20 cm, deep 50 cm or so ” “ eggs hang, in the pits to lay eggs.Producing BI to cover, and then back to the sea.The annual spawn several times, 157 per production 91 ~.Egg white, round, 41 ~ 43 mm diameter, shell, the Shura soft leather quality.Incubator 50 ~ 70 days.
Sea turtle life up 152 years, is animal well-deserved 老寿星 animals longest life expectancy — turtles turtles as early as the emergence of 230 million years ago, on the planet is the famous ” “ living fossils.As far as the world of Guinness record, the turtle's life up 152 years, is a well-deserved 老寿星 in animals.Precisely because the turtle is the longevity of animals in the ocean, so the people along the instruction will still be turtle regarded as the mascot of longevity, just as the mainland people with pine trees the same as a symbol of longevity, coastal people also turn the turtle seen as a symbol of longevity, and have ” “ Wannian turtle. The ocean is currently a total of eight species of sea turtles, where there are four produced in our country, principally in Shandong and Fujian, Taiwan and Hainan, Zhejiang and Guangdong coast, the maximum number of our group is the green turtles.
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In the ocean Live 8 species of sea turtles: a leatherback turtle, hawksbill turtles and red head, olive green squamous turtle, big turtles, green sea turtles, black turtle (Pacific Lepidochelys) peace back turtles.All of the sea turtles were classified as endangered species.
Since male turtles and young turtles go ashore, we will not be very difficult to know the sea turtle survival in the wild.The number of the sea turtles are generally calculated according to their hatching rate.
Research shows that all kinds of immature sea turtles are different degrees of diminished.Especially big turtles and leatherback turtles, all sea turtle disappearing kinds of greatest risk.The maximum number is olive green squamous turtle several to the Indian coast nesting.
Green turtle (Chelonia mydas) body large and heavy carapace length of about 0.7 ∼ 1 meters, weighing about 1.4 kilograms. ∼ 90The largest body length about 1.2 meters above sea level, 585 kilograms in weight.Carapace width and smooth, full-body-Brown or light green, distributed in coastal areas of the world; the main warm waters; feeding of seaweed and unlike other turtles sometimes ashore in the Sun.
Caretta caretta turtle () for a large, similar to the green turtles, but the larger head.Micro-reddish-brown or brown carapace length of about 0.7 ∼ 2.1 meters.Large specimens General weighing about 135 kilograms, but nearly 400 kilograms in weight.It is rumored that their temperament ferocious carnivorous, spread throughout the world's oceans.
Eretmochelys imbricata) hawksbill (body smaller.Its scientific name according to the carapace arranges the overlying plate of tile.The warm waters around the world ocean.Aggressive to feed animals and plants.KAB long about 40 ∼ ∼ 55 cm (16, 22-inch) weighs about 45 kilograms of 13 ∼ ∼ 100 pounds (29).
RI Dali turtle l. (Lepidochelys) is a small turtle, width, a circle.Atlantic RI Dali turtle (m. kempii) gray, about 60 ∼ 79 cm.Produced in the Gulf of Mexico, accidental Gulf stream, an East-North-New England, Great Britain and Europe.This kind of turtle and tortoise commonly known as "hybrids", this name originates from people mistook Atlantic RI Dali turtle is green turtles and turtle after generation.Pacific Dali turtle (L. olivacea) on the Indo-Pacific region. warm-water areaThe type of the body is greater than the Atlantic, slightly greenish to animals and plants.
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Turtle is in existence for 1 billion years of prehistoric reptiles.Sea turtle scales and quality of the shell, although you can stay under water for several hours, but still want to regulate body temperature floating surface and breathe.
It is the largest sea turtle, Leatherback turtle as long as 2 metres, over 1 ton.The smallest is olive green squamous turtle, 75 cm long, 40 kg heavier.
Turtle uniqueness is the tortoise shell.It can protect sea turtles are inviolable, let them swim around freely in the harbour.In addition to the leatherback turtle, all of the sea turtles have shells.Leatherback turtles with thick oily skin, presents 5 longitudinal edged ..
And the tortoise, sea turtles which can't be in the head and limbs shrink back to the shell.Like wings-like forelimbs mainly used to promote the turtle forward, and the hind limbs like rudder direction in the grip of travelling time.
In mature male and female turtle prior to the body is the same.When male turtles matures, tail thickened with variable-length, because the reproductive organs in relation to the bottom of the tail.
Different types of sea turtles have different mature age.The hawksbill turtles 3 years old mature, turtles-50-year-old mature.Turtles must be at the land lay their eggs, once can yield 50-200 a ping-pong ball-shaped eggs, but the chances of young sea turtle survival respirable.
[edit this paragraph] Habitat and range of activities
Most of the sea turtle survival in a relatively shallow coastal waters and bays, lagoons, coral reefs and sea-river estuary.We usually warm and comfortable throughout the world's seas found turtles.
Different kinds and the same type of sea turtle populations within each migration habits.Some turtles to swim to several kilometers away from the nesting and feeding turtles.While the leatherback turtle migration farthest, they want to 5000 kilometers of beach nesting.Black turtle is like in their distribution area of the southernmost and northernmost turtles breeding and feeding.
[edit this paragraph] diet
Turtles whilst no teeth, but their beak but very sharp, different species have different eating habits.Turtle is divided into plant-eating, meat and omnivorous.
Red-headed turtle and tortoise and squamous cell, you can have JAWS milled crabs, some coral Mollusca, jellyfish.While the hawksbill turtle's upper beak hook Qu resembling olecranon, available from the coral interstices identify sponge, shrimps and squid.Green Turtle and black turtle palate assumes the jagged, mainly eats the seaweed and algae.
Turtles eat aquatic plants also swallowed seawater, ingest a large number of salt.Beside the sea turtle some special of the lacrimal gland expel these salts, creating a sea turtles on the shore of “ tears ” phenomenon.
[edit] this paragraph survive threat
Mainly hatching areas damaged and illegal poaching.
Incubation area damaged
The development of the beach greatly reduce sea turtle nesting sites.Turtles are no longer ashore incubation for various reasons: human activities and noise pollution and waste barricaded the turtles way, and if turtles eat the rubbish they may die; Beach man-made light allow turtles to mistake is misled them in the daytime, evening incubation, it will make just hatching out want to go back to sea turtles lose direction.In India Orissa incubation of olive green sea turtles are also facing serious threats.
Illegal poaching
Turtle shells are used to tabulate Combs, spectacle frames, jewelry and other cosmetics and priced very expensive.Turtle fat was used to make soup, sea turtle eggs is also considered wild game.
[edit this paragraph] sea turtle protection
Sea turtle protection work into a high-speed development period, coastal economic activities and harmful fishing operations subject to monitoring.Sea turtle conservation work has been much progress has been achieved.Australia has launched a project, investing millions of dollars in community in the turtle conservation activities, and trying to find ways to solve the problem of ghost nets.Indonesia is conducting an advanced study to determine the fishing industry and the turtle survival status of mutual relations, and with industry to develop appropriate mitigation measures.Seychelles have developed innovative ways to make the participation of private enterprise to actual conservation action.At present, eight countries have already begun implementation focuses on turtle protection of national plans, whereas the other ten countries are also plans to introduce similar schemes.Decades, Austria, Oman, Seychelles and South Africa are monitoring the number of various since sea turtle; otherwise several countries in the last decade have also implemented a protection scheme.United Nations Environment Programme (UNEP) in Bangkok Office is responsible for coordinating the agreement executed by Douglas Hykle said, this national report made it clear that countries are making greater efforts, monitoring, management and protection of the countries of the turtles.
The quantity of green turtles in Sudan, Oman, but in Indonesia and the Philippines, due to unsustainable poaching turtle eggs and collected, the quantity of green turtles.It is reported in the Indian Embassy in the nest, thousands of Lepidochelys quantity continues to decline.While in Thailand, Lepidochelys quantity has been very scarce, it is estimated the number only and has a history of 5 per cent of the high level. Signatory pointed out that natural phenomena such as predator-prey is the largest sea turtle facing threats, immediately following it is incidental capture of coastal fisheries issues.It is reported both threats involving 18 countries by about 35 per cent of the scene in strength is “ moderate to strong ”.In 14 countries of the 20 per cent of field investigations, turtle egg collection have serious threats at all ranks third.After a thorough investigation, the traditional turtle meat and turtle egg consumption remains at three quarters of the signatory States.
Fishery is also becoming the focus of concern.Half of the signatory to the report of fixed gill net have severe effects on sea turtle.Shrimp trawling cause turtle become Deputy catches by, has been a serious problem, however, only one signatory taken effective measures to solve this problem.There are other harmful illegal fishing activities have been put on record, some destructive fishing methods start coming back, such as the use of explosives and poison.
The development of coastal areas, such as the negative consequences of tourism, has also become a focus of attention.The project's Advisory Committee, said Dr Jack Frazier: “ in most of the Indian Ocean region, coastal development, particularly tourism facilities construction quickly.On sea turtle nesting beaches and turtle foraging and rest of the nearshore beaches, the negative effects caused by growing significantly.”
Is expected to have more than 30 countries of the official delegation will attend the Bali meeting.The meeting will discuss an ambitious conservation and management plan to implement the programme involves the field of the 24 project.The meeting will focus case studies, including coastal development problems, fisheries and the turtle of a large project in India and Indonesia to tuna longline fishing industry.The meeting also discusses the establishment of a turtle and endangered habitats in the network.
Recently also will introduce some sharing of information and monitoring turtle number of new tools, such as recently upgraded IOSEA online reporting system.The line database at: , website involved, the Indian Ocean and Southeast Asian turtle haunted 700 key locations.Users can query the system to obtain relevant information, such as a sea turtle species occur, they place in a particular threat faced by, and is implementing mitigation measures that ongoing research activities.Google maps provide all information of high resolution satellite images.
[edit] law of this paragraph
All turtles are in the CITES Convention (CITES) law protection, does not allow any turtle products traded.Even from abroad brings any turtle products are an offence.
Sea turtles there is not currently enlisted in the list of animal protection in China.But as the international wildlife trade one of the Convention on the Member States, China always supports prohibit any turtle products traded.
[edit] network of this paragraph the words
Overseas officers.Formerly ” “ returned, and now use more is known as “ turtles homonym ”. This is known as the network.
[edit the value of this paragraph] diet therapy
Turtle species turtle meat.The distribution of the Yellow Sea turtles and South China Sea.Get the main extraction, after the flesh and blood standby.
Sexual taste flat.Be delicious, moistening the cough.For ganshenyingxuxing, hot flashes, night sweats or dryness and Yin with lung, gasp cough short gas, etc.Can be cooking or fried soup.
成纤维细胞(fibroblast)是疏松结缔组织的主要细胞成分,由胚胎时期的间充质细胞(mesenchymal cell)分化而来。
成纤维细胞较大,轮廓清楚,多为突起的纺锤形或星形的扁平状结构,其细胞核呈规则的卵圆形,核仁大而明显。
根据不同功能活动状态,可将细胞划分成成纤维细胞和纤维细胞,成纤维细胞功能活动旺盛,细胞质嗜弱碱性,具明显的蛋白质合成和分泌活动,在一定条件下,它可以实现跟纤维细胞的互相转化。成纤维细胞对不同程度的细胞变性、坏死和组织缺损以及骨创伤的修复有着十分重要的作用。
参考资料:
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结缔组织(connective tissue)由细胞和大量细胞间质构成,结缔组织的细胞间质包括基质、细丝状的纤维和不断循环更新的组织液,具有重要功能意义。细胞散居于细胞间质内,分布无极性。广义的结缔组织,包括液状的血液、淋巴,松软的固有结缔组织和较坚固的软骨与骨;一般所说的结缔组织仅指固有结缔组织而言。结缔组织在体内广泛分布,具有连接、支持、营养、保护等多种功能。
结缔组织在动物体内分布广,种类多,包括固有结缔组织(疏松结缔组织、致密结缔组织、网状组织、脂肪组织),血液、淋巴,软骨和骨组织,它们都有共同的特征:
它们都起源于胚胎性结缔组织——间充质。在它们的组成成分中除细胞外,还有大量非细胞物质(无定形基质和纤维)。
结缔组织均起源于胚胎时期的间充质(mesenchyme)。间充质由间充质细胞和大量稀薄的无定形基质构成。间充质细胞呈星状,细胞间以突起相互连接成网,核大,核仁明显,胞质弱嗜碱性(图3-1)。间充质细胞分化程度低,在胚胎时期能分化成各种结缔细胞、内皮细胞、平滑肌细胞等。成体结缔组织内仍保留少量未分化的间质细胞。
图3-1 间充质固有结缔组织(connective tissue proper),按其结构和功能的不同分为疏松结缔组织、致密结缔组织、脂肪组织和网状组织。 [编辑本段]一、疏松结缔组织疏松结缔组织(loose connective tissue)又称蜂窝组织(areolar tissue),其特点是细胞种类较多,纤维较少,排列稀疏。疏松结缔组织在体内广泛分布,位于器官之间、组织之间以至细胞之间,起连接、支持、营养、防御、保护和修复等功能。
疏松结缔的组成如下:
(一)细胞
疏松结缔的细胞种类较多,其中包括成纤维细胞、巨噬细胞、浆细胞、肥大细胞、脂肪细胞、未分化的间充质细胞。此外,血液中的白细胞,如嗜酸性粒细胞、淋巴细胞等在炎症反应时也可游走到结缔组织内。各类细胞的数量和分布随疏松结缔组织存在的部位和功能状态而不同。
图3-2 疏松结缔组织铺片模式图1.成纤维细胞 成纤维细胞(fibroblast)是疏松结缔组织的主要细胞成分。细胞扁平,多突起,呈星状,胞质较丰富呈弱嗜碱性。胞核较大,扁卵圆形,染色质疏松着色浅,核仁明显(图3-2)。在电镜下,胞质内富于粗面内质网、游离核糖体和发达的高尔基复合体,表明细胞合成蛋白质功能旺盛(图3-3,3-4)。成纤维细胞既合成和分泌胶原蛋白,弹性蛋白,生成胶原纤维、网状纤维和弹性纤维,也合成和分泌糖胺多糖和糖蛋白等基质成分。
成纤维细胞处于功能静止状态时,称为纤维细胞(fibrocyte)(图3-3)。细胞变小,呈长梭形,胞核小,着色深,胞质内粗面内质网少、高尔基复合体不发达。在一定条件下,如创伤修复,结缔再生时,纤维细胞又能再转变为成纤维细胞。同时,成纤维细胞也能分裂增生。
3-3成纤维细胞左和纤维细胞右超微结构模式
成纤维细胞常通过基质糖蛋白的介导附着在胶原纤维上。在趋化因子(如淋巴因子、补体等)的吸引下,成纤维细胞能缓慢地向一定方向移动。
2.巨噬细胞 巨噬细胞(macrophage)是体内广泛存在的具有强大吞噬功能的细胞。在疏松结缔组织内的巨噬细胞又称为组织细胞(histiocyte),常沿纤维散在分布,在炎症和异物等刺激下活化成游走的巨噬细胞。巨噬细胞形态多样,随功能状态而改变,通常有钝圆形突起,功能活跃者,常伸出较长的伪足而形态不规则。胞核较小,卵圆形或肾形,多为偏心位,着色深,核仁不明显,胞质丰富,多呈嗜酸性,含空泡和异物颗粒,电镜下,细胞表面有许多皱褶、小泡和微绒毛,胞质内含大量初级溶酶体、次级溶酶体、吞噬体、吞饮小泡和残余体。细胞膜附近有较多的微丝和微管(图3-5,3-6)。
巨噬细胞是由血液内单核细胞穿出血管后分化而成。此时,细胞变大,线粒体及溶酶体增多,粘附和吞噬能力增强。在不同组织器官内的巨噬细胞存活时间不同,一般为2个月或更长。
巨噬细胞有重要的防御功能,它具有趋化性定向运动、吞噬和清除异物及衰老伤亡的细胞、分泌多种生物活性物质以及参与和调节人体免疫应答等功能。
(1)趋化性定向运动:巨噬细胞可沿某些化学物质的浓度梯度进行定向移动,聚集到产生和释放这些化学物质的病变部位,这种特性称为趋化性(chemotaxis)。这类化学物质称为趋化因子(chemotactic factor),如补体C5a、细菌的产物、炎症组织的变性蛋白等。
(2)吞噬作用:巨噬细胞具有强大的吞噬能力,包括非特异性吞噬作用和特异性吞噬作用。巨噬细胞经趋化性定向运动抵达病变部位时,即伸出伪足并粘附和包围细菌、异物、衰老伤亡的细胞等,进而摄入胞质内形成吞噬体或吞饮小泡。吞噬体、吞饮小泡与初级溶酶体融合,形成次级溶酶体,异物颗粒被溶酶体酶消化分解后,成为残余体。
在非特异性吞噬过程中,巨噬细胞直接识别和粘附被吞噬物,如碳粒、粉尘、衰老的细胞和某些细菌。巨噬细胞表面有多种受体,有的能与抗体结合(Fc受体);有的能与补体结合(C3受体);有的能与纤维粘连蛋白结合(纤维粘连蛋白受体),在特异性吞噬过程中,抗体,补体、纤维粘连蛋白作为识别因子先将细菌、病毒、异体细胞、受损伤的细胞等包裹起来,通过它们与巨噬细胞表面相应的受体结合,才能被巨噬细胞识别和粘附,启动巨噬细胞的吞噬过程,并显著增强吞噬作用(图3-7)。这种免疫吞噬作用是巨噬细胞重要的功能特征。
(3)分泌作用 :巨噬细胞有活跃的分泌功能,能合成和分泌数十种生物活性物质,如溶菌酶(lysozyme)、干扰素(interferon)、补体(complement)等参与机体的防御功能。还能分泌血管生成因子、造血细胞集落刺激因子、血小板活化因子等激活和调节有关细胞功能活动的多种物质。
(4)参与和调节免疫应答:巨噬细胞能捕捉、加工处理和呈递抗原。被巨噬细胞捕捉的抗原经加工处理后,与主要组织相容性复合体(MHC)的Ⅱ类基因产物结合,形成抗原-MHCⅡ类分子复合物贮存在巨噬细胞表面、并呈递给淋巴细胞,启动淋巴细胞发生免疫应答。其次,巨噬细胞本身也是免疫效应细胞,活化的巨噬细胞能杀伤病原体和肿瘤细胞。此外,巨噬细胞分泌的某些生物活性物质如白细胞介素Ⅰ(interleukinⅠ,IL-Ⅰ)、干扰素等也参与调节免疫应答。
3.浆细胞 浆细胞(plasma cell)通常在疏松结缔组织内较少,而在病原菌或异性蛋白易于入侵的部位如消化道、呼吸道固有层结缔组织内及慢性炎症部位较多。细胞卵圆形或圆形,核圆形,多偏居细胞一侧,染色质成粗块状沿核膜内面呈辐射状排列。胞质丰富,嗜碱性,核旁有一浅染区(图3-2)。电镜下,胞质内含有大量平行排列的粗面内质网和游离的多核糖体。发达的高尔基复合体和中心体位于核旁浅染区内(图3-8,3-9)。
浆细胞具有合成、贮存与分泌抗体(antibody)即免疫球蛋白(immunoglobulin,Ig)的功能,参与体液免疫应答。浆细胞来源于B淋巴细胞。在抗原的反复刺激下,B淋巴细胞增殖、分化,转变为浆细胞,产生抗体。抗体能特异性地中和、消除抗原。
4.肥大细胞 肥大细胞(mast cell)较大,呈圆形或卵圆形,胞核小而圆,多位于中央。胞质内充满异染性颗粒,颗粒易溶于水(图3-2)。电镜下,颗粒大小不一,圆形或卵圆形,表面有单位膜包裹,内部结构常呈多样性,在深染的基质内含螺状或网格状晶体,或含细粒状物质(图3-10)。肥大细胞分布很广,常沿小血管和小淋巴管分布。
肥大细胞与变态反应有密切关系。肥大细胞合成和分泌多种活性介质,包括组胺(histamine)、嗜酸性粒细胞趋化因子(ECF-A)、白三烯(leukotriene)和肝素(heparin)等。组胺、白三烯能使细支气管平滑肌收缩,使微静脉及毛细血管扩张,通透性增加。嗜酸性粒细胞趋化因子能吸引嗜酸性粒细胞到变态反应的部位,肝素则有抗凝血作用。组胺、嗜酸性粒细胞趋化因子和肝素等合成后贮存于颗粒内并能迅速释放。释放时颗粒合并,形成脱粒管道,开口于细胞表面;白三烯则不在颗粒内贮存,其释放较组胺等迟缓(图3-11)。
肥大细胞脱颗粒、释放介质是一种特异性反应。机体受过敏原(如花粉、某些药物等)的刺激后,浆细胞产生亲细胞性抗体IgE。肥大细胞膜表面有IgE受体,当IgE与肥大细胞的IgE受体结合后,机体即对该过每原呈致敏状态。当机体再次接触相同的过敏原时,少量的过敏原便可与肥大细胞上的IgE结合,启动肥大细胞脱颗粒,释放介质,引起过敏反应(图3-11),如在皮肤引起荨麻疹,在呼吸道引起支气管哮喘等。
一般认为,肥大细胞的祖细胞来源于骨髓,经血流迁移到结缔组织内,发育为肥大细胞。组织内的肥大细胞可分裂增殖,其寿命数天至数月。
5.脂肪细胞 脂肪细胞(fat cell)常沿血管分布,单个或成群存在。细胞体积大,常呈圆球形或相互挤压成多边形。胞质被一个大脂滴推挤到细胞周缘,包绕脂滴。核被挤压成扁圆形,连同部分胞质呈新月形,位于细胞一侧。在HE标本中,脂滴被溶解,细胞呈空泡状(图3-2)。脂肪细胞有合成和贮存脂肪、参与脂质代谢的功能。
6.未分化的间充质细胞 未分化的间充质细胞(undifferentiated mesenchymal cell)是保留在成体结缔组织内的一些较原始的细胞,它们保持着间充质细胞的分化潜能,在炎症与创伤时可增殖分化为成纤维细胞、脂肪细胞。间充质细胞常分布在小血管尤其是毛细血管周围,并能分化为血管壁的平滑肌和内皮细胞。
7.白细胞 血液内的白细胞,受趋化因子的吸引,常穿出毛细血管和微静脉,游走到疏松结缔组织内,行使其功能,参与免疫应答和炎症反应。疏松结缔组织内以嗜酸性粒细胞、淋巴细胞、中性粒细胞多见。游走出的单核细胞将分化为巨噬细胞。 [编辑本段]二、纤维
1.胶原纤维 胶原纤维(collagenous fiber)数量最多,新鲜时呈白色,有光泽,又名白纤维。HE 染色切片中呈嗜酸性,着浅红色。纤维粗细不等,直径1-20μm,呈波浪形,并互相交织。胶原原纤维由直径20~200nm的胶原原纤维粘合而成(图3-2)。电镜下,胶原原纤维显明暗交替的周期性横纹,横纹周期约64nm(图3-12)。胶原纤维的韧性大,抗拉力强。胶原纤维的化学成分为Ⅰ型和Ⅱ型胶原蛋白。胶原蛋白(简称胶原,collagen)主要由成纤维细胞分泌。分泌到细胞外的胶原再聚合成胶原原纤维,进而集合成胶原纤维。
胶原纤维形成的基本过程如下(图3-13):
(1)细胞内合成前胶原蛋白分子:成纤维细胞摄取合成蛋白质所需的氨基酸,包括脯氨酸、赖氨酸和甘氨酸,在粗面内质网的核糖体上按照特定的胶原mRNA的碱基序列,合成前α-多肽链。后者边合成边进入粗面内质网腔内,并在羟化酶的作用下,将肽链中的脯氨酸和赖氨酸羟化。经羟化后,三条前α-多肽链互相缠绕成绳索状的前胶原蛋白分子(procollagen molecule)。溶解状态的前胶原蛋白分子,两端未缠绕,呈球状构型,在粗面内质网腔内或转移到高尔基复合体内加入糖基后,分泌到细胞外。
(2)原胶原蛋白分子的细胞外聚合:细胞外的前胶原蛋白分子,在肽内切酶的作用下,切去分子两端球状构形部分,形成原胶原蛋白分子(tropocol-lagen)粗约1.5nm,长约300nm。原胶原蛋白分子平行排列聚合成胶原原纤维。聚合时,相互平行的相邻分子错开1/4分子长度,同一排的分子,首尾相对并保持一定距离,聚合成束,于是形成具有64nm周期横纹的胶原原纤维。聚合时,分子内、分子间的化学基因进行缩合、交联,增加原纤维的稳固性。若干胶原原纤维经糖蛋白粘合成粗细不等的胶原纤维。
胶原纤维的一菜成受多方面的影响和调控。如细胞内脯氨酸的含量直接影响前α-多肽链的合成。缺氧或缺乏维生素C或Fe2+等辅助因子,导致前α-多肽链的羟化受到抑制,造成前胶原蛋白合成障碍,影响创伤的愈合。聚合时,如胶原蛋白分子内和分子间的交联障碍(常因赖氨酰氧化酶不足所致)将影响胶原纤维的稳固性。除成纤维细胞外,成骨细胞、软骨细胞、某些平滑肌细胞等起源于间充质的细胞以及多种上皮细胞也能产生胶原蛋白。
不同组织的胶原蛋白其分子类型不同,已证实α-多肽链按其一级结构分为α1,α2,α3,三类,各类又分为10型,如α1(Ⅰ)、α1(Ⅱ)、α1(Ⅲ)、α1(Ⅲ)……α1(X)。
根据构成胶原蛋白三股肽链的不同,现已发现有11种不同类型的胶原。现将主要几种类型的组成、分布和特点列举于表(表3-1)。
表3-1 胶原蛋白的类型、分布和特点
类型 前胶原蛋白的三股肽链 分布 主要特点
Ⅰ [α1(Ⅰ)]2α2(Ⅰ) 真皮、筋膜、巩膜、被膜、腱、纤维软骨、骨、牙本质 构成致密并有横纹的粗纤维束,抗拉力强
Ⅱ [α1(Ⅱ)]3 透明软骨和弹性软骨 构成有横纹的细原纤维,抗压力较强
Ⅲ [α1(Ⅲ)]3
[α1(Ⅳ)]2α2(Ⅳ)
网状纤维、平滑肌、神经内膜、动脉、肝、脾、肾、肺、子宫 构成有横纹的细原纤维,维持器官的形态结构
Ⅳ [α1(Ⅳ)]3
[α2(Ⅳ)]3
[α1(Ⅴ)]2α2(Ⅴ)
基膜基板、晶 状体囊 不形成原纤维,为均质状膜,支持和滤过作用
Ⅴ [α1(Ⅴ)]3
α1(Ⅴ)α2(Ⅴ)α3(Ⅴ)
胎膜、肌、腱鞘 构成细的无横纹原纤维
2.弹性纤维 弹性纤维(elastic fiber)新鲜状态下呈黄色,又名黄纤维。在HE标本中,着色轻微,不易与胶原纤维区分。但醛复红(aldehyde-fuchsin)或地衣红(orcein)能将弹性纤维染成紫色或棕褐色。弹性纤维较细,直行,分支交织,粗细不等(0.2-1.0μm),表面光滑,断端常卷曲(图3-2)。电镜下,弹性纤维的核心部分电子密度低,由均质的弹性蛋白(elastin)组成,核心外周覆盖微原纤维(microfibril),直径约10nm。弹性蛋白分子能任意卷曲,分子间藉共价键交联成网。在外力牵拉下,卷曲的弹性蛋白分子伸展拉长;除去外力后,弹性蛋白分子又回复为卷曲状态(图3-14)。
弹性纤维富于弹性而韧性差,与胶原纤维交织在一起,使疏松结缔组织既有弹性又有韧性,有利于器官和组织保持形态位置的相对恒定,又具有一定的可变性。
3.网状纤维 网状纤维(reticular fiber)较细,分支多,交织成网。网状纤维由Ⅲ型胶原蛋白构成,也具有64nm周期性横纹。纤维表面被覆蛋白多糖和糖蛋白,故PAS反应阳性,并具嗜银性。用银染法,网状纤维呈黑色,故又称嗜银纤维(argyrophil fiber)。网状纤维多分布在结缔组织与其它组织交界处,如基膜的网板、肾小管周围、毛细血管周围。在造血器官和内分泌腺,有较多的网状纤维,构成它们的支架。 [编辑本段]三、基质基质(ground substance)是一种由生物大分子构成的胶状物质,具有一定粘性。构成基质的大分子物质包括蛋白多糖和糖蛋白。
蛋白多糖(proteoglycan)是由蛋白质与大量多糖结合成的大分子复合物,是基质的主要成分。其中多糖主要是透明质酸(hyaluronic acid),其次是硫酸软骨素A 、C(chondroitin sulfate A、C)、硫酸角质素A、C(keratin sulfate)硫酸乙酰肝素(heparan sulfate)等。它们都是以含有氨基已糖的双糖为基本单位聚合成的长链化合物,总称为糖胺多糖(glycosaminoglycan,GAG)。由于糖胺多糖分子存在大量阴离子,故能结合大量水(结合水)。透明质酸是一种曲折盘绕的长链 大分子,拉直可达2.5μm,由它构成蛋白多糖复合物的主干,其它糖胺多糖则以蛋白质为核心构成蛋白多糖亚单位,后者再通过连接蛋白结合在透明质酸长链分子上(图3-15)。蛋白多糖复合物的立体构型形成有许多微孔隙的分子筛,小于孔隙的水和溶于水的营养物、代谢产物、激素、气体分子等可以通过,便于血液与细胞之间进行物质交换。大于孔隙的大分子物质,如细菌等不能通过,使基质成为限制细菌扩散的防御屏障。溶血性链球菌和癌细胞等能产生透明质酸酶,破坏基质的防御屏障,致使感染和肿瘤浸润扩散。
图3-15 蛋白多糖分子结构模型
糖蛋白(glycoprotein)是基质内另一类重要的生物大分子,与蛋白多糖相反,其主要成分是蛋白质。从基质内已经分离出多种糖蛋白,主要的有纤维粘连蛋白(fibronectin FN)层粘连蛋白(laminin)和软骨粘连蛋白(chondronectin)等。这类基质大分子不仅参与基质分子筛的构成,同时通过它们的连接和介导作用也影响细胞的附着和移动以及参与调节细胞的生长和分化。
纤维粘连蛋白是基质中一种重要的糖蛋白,存在于胶原纤维和许多结缔组织细胞周围。在电镜下,纤维粘连蛋白呈原纤维状,由两条多肽链组成,两条肽链的一端由若干二硫键连接。每一肽链上均有若干特定的功能区,能分别与细胞、胶原、肝素和纤维素等结合。于是,纤维粘连蛋白作为一种中介蛋白,能将细胞连接到胶原、肝素等细胞外基质上。
组织液(tissue fluid)是从毛细血管动脉端渗入基质内的液体,经毛细血管静脉端和毛细淋巴管回流入血液或淋巴,组织液不断更新,有利于血液与细胞进行物质交换,成为组织和细胞赖以生存的内环境。当组织液的渗出、回流或机体水盐、蛋白质代谢发生障碍时,基质中的组织液含量可增多或减少,导致组织水肿或脱水。 [编辑本段]四、致密结缔组织致密结缔组织(dense connctive tissue)的组成与疏松结缔组织基本相同,两者的主要区别是,致密结缔组织中的纤维成分特别多,而且排列紧密,细胞和基质成分很少。除弹性组织外,绝大多数的致密结缔组织中以粗大的胶原纤维束为主要成分,其中含少量纤维细胞、小血管和淋巴管。按纤维的性质和排列方式不同,可将致密结缔组织分为以下几种类型:
1.不规则致密结缔组织分布于真皮的网状层、巩膜
、大多数器官的被膜等处。以胶原纤维为主,粗大的胶原纤维束互相交织成致密的网或层。纤维的走行方向与承受机械力学作用的方向相适应。纤维束间有少量基质和成纤维细胞、纤维细胞、小血管及神经束等。
2.规则致密结缔组织肌胆为其典型代表。胶原纤维束平行而紧密排列,束间有沿其长轴成行排列的细胞,称腱细胞,它是一种变形的成纤维细胞,胞体伸出许多翼状突起,插入纤维束间并将其包裹。细胞的横切面呈星形,核 位于细胞的中央。
3.弹性组织(elastic tissue)是富于弹性纤维的致密结缔组织,如项韧带、黄韧带、声带等。由粗大的弹性纤维平行排列成柬,并以细小的分支连接成网,其间有胶原纤维和成纤维细胞。
体内有很多部位的结缔组织是疏松与致密结缔组织之间的过渡形态,其结构特点是:由较细密的胶原纤维、弹性纤维和网状纤维交织成网,其中含有较多的细胞成分、小血管和神经等。如消化道、呼吸道粘膜固有层的结缔组织即属于此种,常称其为细密的结缔组织。 [编辑本段]五、脂肪组织脂肪组织(adipose tissue)主要是由大量脂肪细胞集聚而成。疏松结缔组织将成群的脂肪细胞分隔成许多脂肪小叶。根据脂肪细胞的结构和功能不同,可分为两种脂肪组织:
1.白色(黄色)脂肪组织(white,yellow adipose tissue)白色脂肪组织中脂肪细胞的结构特点是:①胞质内含有一个大的脂肪滴,位于细胞的中央,在HE染色标本上因脂肪滴被溶解而成大空泡状;②很少的胞质及扁椭圆形的胞核被挤在周边,此种细胞称为单泡脂肪细胞。成人大多数的脂肪细胞均属此类,如皮下组织、系膜、网膜和黄骨髓等。脂肪组织除具有支持、缓冲保护和维持体温的功能外,还是机体贮存脂肪的“脂库”。
2.棕色脂肪组织(brown adipose tissue)棕色脂肪组织中含有丰富的血管和神经。棕色脂肪细胞的特点是:①细胞呈多边形,胞质内有许多较小的脂滴和大而密集的线粒体,线粒体与脂滴紧密相贴;②核圆位于细胞中央,称此种细胞为多泡脂肪细胞。棕色脂肪在新生儿含量较多,成人含量很少。在冬眠动物的体内也较多。在寒冷的环境下,棕色脂肪细胞内的脂类迅速氧化,产生大量热能,有利于新生儿的抗寒和维持冬眠动物的体温。
四)网状组织
网状组织(reticular tissue)是由网状细胞、网状纤维和基质组成。
1.网状细胞(reticular cell)为星形多突起细胞,其突起彼此连接成网。胞质弱嗜碱性。核较大、椭圆形、染色浅、核仁清楚。
2.网状纤维网状纤维细而多分支,沿着网状细胞的胞体和突起分布(即网状 细胞附于其上)。网状纤维分支互相连接成的网孔内充满基质(在淋巴器官和造血器官分别是淋巴液和血液)。 体内没有单独存在的网状组织,它是构成淋巴组织、淋巴器官和造血器官的基本组成成分。分布于消化道、呼吸道粘膜固有层、淋巴结、脾、扁桃体及红骨髓中。在这些器官中,网状组织成为支架,网孔中充满淋巴细胞和巨噬细胞,或者是发育不同阶 段的各种血细胞。网状细胞则成为T、B淋巴细胞和血细胞发育微环境的细胞成分之一。 [编辑本段]六、结缔组织的一般特点结缔组织的一般特点
结缔组织由大量的细胞间质和散在其中的细胞组成。细胞种类较多,数量较少,分散而无极性。细胞间质包括基质、纤维和组织液。基质是无定形的胶体样物质,纤维为细丝状,包埋在基质中。
结缔组织分布广泛,形态多样。如纤维性的肌腱、韧带、筋膜;流体状的血液;固体状的软骨和骨等。在机体内,结缔组织主要起支持、连接、营养、保护等多种功能。
各类结缔组织的结构及其功能
结缔组织可分为:疏松结缔组织、致密结缔组织
德国FIBRO公司1958年成立,先后在法国、瑞士、美国、新加坡、印度和中国设立分公司。FIBRO是模具标准件行业国际标准的制定者之一。FIBRO的客户范围很广,特别是汽车模具行业,是宝马、奔驰和大众等知名汽车品牌指定模具标准件供应商。对于FIBRO这个在国际市场上已经成熟的企业,在2010年才进入中国的市场。FIBRO模具标准件的类型有6万5千余种,产品种类满足工具制造、模具制造、机械等领域的客户需求,主要产品涵盖钢制导柱模架、导向元件、几乎不需维护的滑动元件、精密件如冲裁凸模、冲裁衬套、钢质特种压力弹簧、氮气弹簧、模具材料、金属粘合剂和浇铸树脂、压力机和模具制造的外围设备、带楔形传动等的模具楔块装置,其中FIBRO的氮气弹簧是世界顶级的.FIBRO产品一向以高品质和完善的服务在全球市场上赢得客户的口碑。FIBRO公司有一套严苛的质量管理体系,实行整个流程管控体系,从生产检测—材料检测—硬化过程—产品总检,每一步都实现专业化管控。
具体在中国怎么样就不清楚了 哈哈
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